Semi auto air guns are driven by C02 gas. When the trigger is pulled some of the C02 not only fires the projectile but drives gears that get the next pellet or bb in line to fire the next projectile.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.